1. Field of the Invention
This invention relates to water aeration and more specifically this invention relates to a device for aerating surface water.
2. Background of the Invention
Bodies of surface water, either manmade or naturally occurring, maintain their viability partly by their physical interaction with elements of the environment. Such interaction includes aeration and agitation caused by wind movement, fish and animal activity, seasonal inversions and in-rushing water from underground springs.
Oftentimes however, surface waters suffer eutrophic conditions due to low oxygen, high carbon dioxide levels. Eutrophic conditions occur for a number of reasons, including the existence of a high biological load whereby organisms use more oxygen and create more carbon dioxide than fauna create and utilize, respectively. Eutrophic waters also result from "still" water conditions wherein oxygenation is initially low due to shelter from wind, or due to a lack of water ingress or egress. Once a eutrophic condition establishes itself, an explosion of surface vegetation occurs, such as algae. With the algae comes an exacerbation of the problem inasmuch as air-exchange with the water surface is further inhibited, as is the penetration of oxygen-generating sunlight (via photosynthesis) to lower water depths.
Low oxygen conditions also can be caused by freezing of surface waters. In such situations, sunlight needed to drive oxygen-producing photosynthesis occurring in water fauna is reduced, as is aeration caused by surface winds. Winter kill of fish due to low dissolved oxygen (DO) levels is common, particularly in northern climes.
Also, treatment of organic waste in surface waters, such as what occurs in municipal sanitation systems, requires the introduction of appreciable amounts of oxygen. Without such oxygen injections, eutrophic conditions abound due to high biological load of degrading bacteria.
A myriad of methods for aerating surface waters have been utilized in efforts to eliminate or at least minimize low oxygen environs as described above. However, most of these methods utilize complex systems for mixing air and water. Typical of such systems are U.S. Pat. Nos. 4,906,363; 4,828,696; and 4,702,830, all granted to Makino et al. In such designs, air is pumped into a chamber designed to create intermittent bubbles of air encased in a tube (with the diameter of the tube being the same as that of the bubbles). As the bubbles rise to the water surface they push upwards water trapped in the tube above these bubbles.
U.S. Pat. No. 4,687,494 granted to Escobal discloses a system for water agitation that utilizes pumping of both water and air. Similarly, U.S. Pat. No. 4,522,151 granted to Arbisi discloses a device wherein fine bubbles of air are produced within a conduit through which the water is being pumped.
A water pump is utilized in U.S. Pat. No. 3,563,641 granted to Eron, wherein the pump is floating on the surface of the pond. Stream aerators also exist (e.g. U.S. Pat. No. 3,489,396 granted to D'Aragon) and are designed for high velocity fluid flow.
A common disadvantage inherent with many of the devices discussed above is that waste-laden water must traverse intricate pumps and other mechanisms and passageways to ultimately become aerated. These intricate structures are easily obstructed or fouled by icing or by waste carried by the water. The systems can be further damaged by suspended solids and even chemicals found in the water.
A need exists in the art for a simple device for aerating surface waters in all seasons. The device should be constructed with off-the-shelf componentry and be easily maintained, even in the most eutrophic conditions. The device should incorporate no intricate componentry with its design embodying few if any moving parts, turbines or gate valves.